Forming and trimming apparatus for hydroform press

ABSTRACT

A device having separate shape-forming and trim die portions is incorporated in a hydroform press. A blank sheet is placed over the die portions and a diaphragm is placed over the blank sheet. The diaphragm is pressurized with hydraulic fluid and then only the shape-forming die portions are urged into the flexible die element to shape and trim the element in a single cycle of the machine.

United States Patent Martin [4 1 June 27, 1972 s41 FORMING AND TRIMMING2,766,711 10/1956 Dever et al. ..72/s7 APPARATUS FOR HYDROFORM PRESS2,344,743 3/1944 Sm1th, .lr ...72l57 2,859,719 11/1958 Krayb1ll ..72/63[72] Inventor: John J. Martin, Milford, Conn.

1 Primary Examiner-Richard J. Herbst [73] Asslgnee. Avco Corporation,Stratford, Conn. Atmmey Chafles M Hogan and Gary M. Gm [22] Filed: Nov.20, 1970 [57] ABSTRACT [21] App1.No.: 91,288

A device having separate shape-forming and trim die portions isincorporated in a hydroform press. A blank sheet is placed U.S. Cl...72/55, 72/63 over the die ortions and a diaphragm is placed over theblank [51] lnt.Cl ..B2ld 28/18 sheet. The diaphragm is pressurized withhydraulic fluid and [58] Field of Search ..72/55, 57, 63; 18/19 F, DIG.19; then only the shape-forming die portions are urged into the 264/313flexible die element to shape and trim the element in a single cycle ofthe machine. 56 ited 1 References C 5 Claims, 3 Drawing Figures UNITEDSTATES PATENTS 2,719,500 10/ 1955 Kraybill ..72/57 l 1 I I mm W 32 8\ f5 my? INVENTOR. JOHN J. MARTIN ATTORNEYS.

P'A'TE'N'TEDJum m2 SHEET 2 OF 2 INVENTOR JOHN J. MARTIN MUM M. W 7ATTORNEYS.

FORMING AND TRIMMING APPARATUS F HYDROFORM PRESS The present inventionrelates to die elements for use with hydroform shape-forming machines.

Several years ago the process of hydroforming was developed to rapidlyand efficiently form complex parts. Such a machine generally consists ofa rigid male die element which is connected to a hydraulic ram of thehydroform machine. A

7 blank sheet is laid over the rigid die element and a flexible dieelement that forms one wall of a'chamber is positioned over the blanksheet. The pressure in the pressure chamber is increased to an extremelyhigh level, such as 10,000 p.s.i. with hydraulic fluid. This forces theblank sheet element against the contours of the rigid die element. Afterthis initial pressurization the hydraulic ram in the machine is actuatedto displace the rigid die element'along with the-blank sheet into theflexible die element. This greatly increases the stresses in the chamberand causes the blank sheet to conform to the shape of the rigiddieelement. As the rigid die element is pushed into the flexible dieelement, the flexible die element exerts a lateral pressure locking theblank sheet to the contours of the rigid; die element and distributingthe remaining metal uniformly over the entire surface of the die.

This process enables the deep. drawing of many parts in a singleoperation and, as a, result, has greatly decreased manufacturing costsfor the items so formed. However, even with present hydroform machinesadditional steps are necessary to trim the part so formed.

Therefore it is an object of the present invention to form and trim ablank sheet element in a single cycle of a hydroform machine, whilebridging the central portion of the hydraulic ram.

In a machine of the above type the above ends are achieved by anapparatus comprising a rigid shape-forming die displaceable towarda'flexible die of the machine. A trim dieis supported by the machinebase at the same level as the shapeforming die for receiving a blanksheet during initial pressurization of the flexible die. As a result,the blank sheet is formed by pressurization of the' flexible die elementand trimmed by displacement of the shape-forming die element toward theflexible die element.

The above and other related objects and features-of the presentinvention will be apparent from a reading of the description of thedisclosure shown in the accompanying drawings and the novelty thereofpointed out in the appended claims.

In the drawings: v

FIG. 1 is an elevational view of a hydroform machine utilizing apparatusembodying the present invention;

FIG. 2 is an expanded fragmentary view of a portion of the apparatusshown in FIG. 1;

FIG. 3 is a view taken on lines 3-3 of FIG. 2.

Referring now to FIG. 1 there is shown a hydroform machine with whichthe present invention is used. The machine comprises a base 12 fromwhich four massive structural support posts 14 extend vertically. Anadjustable carriage 16, which can be positioned at varying distancesfrom base 12, is guided on posts 14. Carriage 16 has an integral chamberl8which has a flexible die element, such as a rubber diaphragm 20,positioned over one end. The diaphragm 20 is made of material that canwithstand extremely high-pressures, for example, butyl rubber. Forprotection of the butyl rubber diaphragm 20 there is generally anadditional diaphragm 22 positionedover diaphragm 20. A retaining plate24 is secured to carriage 16 by screws (not shown) to hold thediaphragms 20, 22 in place. 7 ,7

The base of the machine 12 has a hydraulic ram or actuating element 28which is displaceable upwards toward diaphragm 20; The ram has a centraloutput shaft 30 which includes a actual machines extends upward frombase 12 and a suitable provision is made in the apparatus describedbelow to make the shaft 30 inoperative.

The apparatus comprises an outer support ring 38 abutting base 12 andappropriately retained in place. Within the outer ring 38 is a ring 44which supports the periphery of a base disc 46 positioned over theactuating rods 32. Base disc 46 has an integral circular trim dieelement 48 which defines the inner diameter of a ringlike finished piecewhich is to be formed froma blank sheet 50. A peripheral trim dieelement 52 is supported by outer ring 38 and, defines the outer diameterof the ringlike finished piece.

An annular shape forming die support 51 is received within an annularraceway 54 defined by the outer and inner trim die elements 52 and 48,respectively. Annular shape-forming die elements 56 are secured to thedie support 51 by means of screws 58. The shape-forming die elements 56may be shaped to produce a number of configurations. However, forpurposes of illustration the shape-forming-die elements are being usedto form shallow recesses 55 around the finished piece which is stackedwith other pieces to form a heat exchanger.

The shape-forming die elements 56 interfit with the trim die elements 52and 48 to define the edges of the finished piece.

The die support 51 is displaceable in raceway 54 towards diaphragm 20 bymeans of a plurality of displaceable rods 60 abutting the bottom surfaceof die support 51 and extending through openings 62 in the base discelement 48. The bottom of rods 60 abut a displaceable disc 64 which ispositioned underneath the base disc 56 and within the peripheral ringsupport 44. The bottom surface of displaceable disc 64 abuts theactuating rods 32 extending from machine base 12 As a result of thisconnection the die support 51. and shape-forming die elements 56 aredisplaceable in an upward direction in response to the displacement ofactuating rods 32. While die elements 48 and 52 remain in place holdingstripped waste material from blank sheet 50, the cycle is completedwithout die element 48 being displaced in an upward direction by theoutput shaft 30. i

In order to support the central portion of the base disc 48 and guidedisplaceable disc 64, a plurality of support rods 66 abut the bottom ofdisc 48 radially inward from the periphery support ring 44. Rods 66extend through openings 68 in the displaceable disc 64 to abut the uppersurface of the machine base 12. v

The finished piece, in addition to having a ringlikeshape, may have aseries of irregular perforations around its periphery, as shown in FIGS.2 and To produce these per forationsa series of perforation trimelements70, 72 are positioned in corresponding recesses 74, 76 positioned aroundthe circumference of the shape-forming die elements 56, as shown 7particularly in FIG. 3. The trim element 70 is supported within recess74 by a pair of pins 78 which extend through suitable openings in thedie support 51 to abut the upper surface of the base disc 46. Theperforation trim element 72 is supported within recess 76 by a pluralityof pins 80'which extend through openings 82, as shown in FIG. 2, to abutthe upper surface of base disc 46. The perforation trim elements 70, 72'are positioned by the pins 78, 80 to be maintained at the same level asthe trim die elements 52 and 48.

It should be noted in FIG. 3 that the displaceable rods-60 arepositioned around the periphery of the die support 5] midway betweeneach of the adjacent perforation trim elements around the circumferenceof the shape-forming die elements 56.

To form a piece the following operation is used: A blank sheet 50 isplaced over the outer and inner trim die elements 52 and 48 and themovable carriage l6 lowered-to position the diaphragm 20 over theblanksheet 50, as shown in FIG. 1. Thepressure in chamber 18 isincreased to a very high level so that the blank sheet is forced bydiaphragm 20 into the recesses 55 formed in the die elements 56/Afterthis is done the actuating rods 32 are displaced upwards. This causesdie elements 56*to be displaced a small amount into the diaphragm 20, asshown in FIG. 2. It should be noted that the trim die elements 52, 48

and also the perforation trim elements 70, 72 remain stationary becausethey are supported by the base disc 46 or the outer retaining ring 38,both of which are supported on the machine base 12. The resultantrelative movement causes the diaphragm 20 to sear off the blank sheet 50at the junction between the trim die elements and the shape-forming dieelements 56. Thus a blank sheet is formed and trimmed in a single cycleof the machine.

It can be seen that the above apparatus is easily installed on astandard hydroform machine and is able to accommodate the actuating rodsbuilt into the machine while still maintaining a rigid support of thedie elements. The base disc 46 not only is supported at its peripherybut is supported directly underneath the central die element 48 tominimize bending stresses produced by the extremely high pressuresexerted over the upper surface of the die elements. At the same timerods 66 act as guides for the even displacement of disc 64 to produce auniform shearing action.

While the above invention has been described in the forming of aringlike disc element, it is apparent that it can be used with equaladvantage to produce other shapes with equal advantage. It is believedthat those skilled in the art can employ additional modifications anduse the apparatus for other forms without departing from the spirit andscope of the present invention.

Having thus described the invention, what is claimed as novel anddesired to be secured by Letters Patent of the United States is:

l. in a forming machine comprising a stationary machine support base, aflexible die element, one side of which is displaceable over a blanksheet placed in said machine, a means for pressurizing the opposite sideof said flexible die element, and an actuating means for urging saidblank sheet toward said flexible die element after the opposite side ofsaid flexible die element is pressurized, apparatus interposed betweensaid machine base and said blank sheet for forming and trimming it to aringlike disc with a series of perforations formed therein around itscircumference in a single operation of the above machine, said apparatuscomprising:

a rigid shape-forming ringlike die displaceable toward said flexible dieelement by said actuating means, said shapeforming die means definingthe ultimate shape and contours of said disc;

trim die means supported by said machine base interfitting with saidshape-forming die means to define the inside and outside diameter ofsaid disc;

a series of perforation trim elements received in recesses conforming tothe shape of said perforation elements around the periphery of saidringlike die element;

a plurality of perforation trim element support pins extending from thebottom surface of said perforation trim elements through openings insaid shape-forming die element to be supported by said machine base;

said shape-forming die and trim die means and perforation trim elementshaving blank sheet receiving surfaces positioned at generally the samelevel for initial pressurization of the opposite side of said flexibledie element, whereby said contours of said disc are formed bypressurization of said flexible die element and said disc is trimmed andperforated by displacement of said rigid shape-forming die toward saidflexible die element.

2. Apparatus as in claim 1 wherein:

said trim die means comprise:

a base disc positioned over said actuating means;

an annular peripheral support ring positioned on said machine base andsupporting the periphery of said base disc above said machine base;

an outer retainer ring element extending around the periphery of saidbase disc and secured to said machine base, outer retainer ring havingan upper support surface above the base disc;

a circular trim die element integral with said base disc and definingthe inner diameter of said ringlike disc;

an annular trim die element supported by said outer retainer ringelement at the same level as said circular trim die element and definingthe outer diameter of said ringlike disc;

said shape-forming die means comprises:

an annular shape-forming die element positioned above said base disc andbetween said trim die elements;

means for connecting said shape-forming elements to said actuating meanswhereby said shape-forming die element is displaced relative to saidtrim elements.

3. Apparatus as in claim 1 wherein said actuating means includes aplurality of axially displaceable actuating rods extending from saidmachine base and in a generally circular pattern, and wherein saidshape-forming die connecting means comprises:

a displaceable disc positioned beneath said base disc and within saidperipheral support ring, said displaceable disc being supported on itsbottom side by said actuating rods;

a plurality of displaceable rods positioned around the periphery of saidcentral disc and extending through holes in said base die to abut thebottom surface of said shapefor'rning die element.

4. Apparatus as in claim I further comprising a plurality of supportrods extending through openings in said displaceable disc and abuttingthe bottom side of said base disc element radially inward of saidperipheral support ring.

5. Apparatus as in claim 4 wherein said perforation trim elements arepositioned at regularly spaced intervals around the circumference ofsaid shape-forming ringlike die element and said perforation trimelement support pins are supported by said base disc and saiddisplaceable rods which abut said shapeforming die element extendthrough holes formed in said base disc between each of the adjacentperforation-forming elements around the periphery of said shape-formingdie element.

1. In a forming machine comprising a stationary machine support base, aflexible die element, one side of which is displaceable over a blanksheet placed in said machine, a means for pressurizing the opposite sideof said flexible die element, and an actuating means for urging saidblank sheet toward said flexible die element after the opposite side ofsaid flexible die element is pressurized, apparatus interposed betweensaid machine base and said blank sheet for forming and trimming it to aringlike disc with a series of perforations formed therein around itscircumference in a single operation of the above machine, said apparatuscomprising: a rigid shape-forming ringlike die displaceable toward saidflexible die element by said actuating means, said shapeforming diemeans defining the ultimate shape and contours of said disc; trim diemeans supported by said machine base interfitting with saidshape-forming die means to define the inside and outside diameter ofsaid disc; a series of perforation trim elements received in recessesconforming to the shape of said perforation elements around theperiphery of said ringlike die element; a plurality of perforation trimelement support pins extending from the bottom surface of saidpErforation trim elements through openings in said shape-forming dieelement to be supported by said machine base; said shape-forming die andtrim die means and perforation trim elements having blank sheetreceiving surfaces positioned at generally the same level for initialpressurization of the opposite side of said flexible die element,whereby said contours of said disc are formed by pressurization of saidflexible die element and said disc is trimmed and perforated bydisplacement of said rigid shape-forming die toward said flexible dieelement.
 2. Apparatus as in claim 1 wherein: said trim die meanscomprise: a base disc positioned over said actuating means; an annularperipheral support ring positioned on said machine base and supportingthe periphery of said base disc above said machine base; an outerretainer ring element extending around the periphery of said base discand secured to said machine base, said outer retainer ring having anupper support surface above the base disc; a circular trim die elementintegral with said base disc and defining the inner diameter of saidringlike disc; an annular trim die element supported by said outerretainer ring element at the same level as said circular trim dieelement and defining the outer diameter of said ringlike disc; saidshape-forming die means comprises: an annular shape-forming die elementpositioned above said base disc and between said trim die elements;means for connecting said shape-forming elements to said actuating meanswhereby said shape-forming die element is displaced relative to saidtrim elements.
 3. Apparatus as in claim 1 wherein said actuating meansincludes a plurality of axially displaceable actuating rods extendingfrom said machine base and in a generally circular pattern, and whereinsaid shape-forming die connecting means comprises: a displaceable discpositioned beneath said base disc and within said peripheral supportring, said displaceable disc being supported on its bottom side by saidactuating rods; a plurality of displaceable rods positioned around theperiphery of said central disc and extending through holes in said basedie to abut the bottom surface of said shape-forming die element. 4.Apparatus as in claim 1 further comprising a plurality of support rodsextending through openings in said displaceable disc and abutting thebottom side of said base disc element radially inward of said peripheralsupport ring.
 5. Apparatus as in claim 4 wherein said perforation trimelements are positioned at regularly spaced intervals around thecircumference of said shape-forming ringlike die element and saidperforation trim element support pins are supported by said base discand said displaceable rods which abut said shape-forming die elementextend through holes formed in said base disc between each of theadjacent perforation-forming elements around the periphery of saidshape-forming die element.